1. Field of the Invention
The invention relates to an endoscope form detecting apparatus for detecting a form of an insertion part, in which a magnetic-field generation element or a magnetic detection element is fixedly mounted within the insertion part of the endoscope, by an insulating member so that the form is not deformed even when the insertion part is curved.
2. Description of the Related Art
In recent years, an endoscope has widely been used in the field of medical treatment and the industrial field. The endoscope, particularly, an endoscope whose insertion part is elastic is inserted into a curved body cavity, to thereby be able to diagnose internal organs in a depth within the body cavity without incision, and can perform medical treatment such as one in which a treatment tool is inserted into a channel, as occasion demands, to excise polyps, or the like.
In this case, as in the case where the interior of a distal or inferior digestive organ is inspected or examined from the side of an anus, for example, there is a certain measure of skill required for the insertion part to be smoothly inserted into the curved body cavity.
Specifically, whenever an inserting operation is performed, an operation where a bending section, which is provided on the insertion part, is curved in accordance with a bending of a line, or the like, is required for performing smooth insertion. To this end, it can be known where the position within the body cavity of a distal end or a forward end of the insertion part, in what manner the insertion part is curved at present, and the like.
For this reason, in the prior art of U.S. Pat. No. 5,273,025, there is disclosed an arrangement in which a non-scanning or standard antenna (antenna coil) which is provided outside the insertion part is scanned with respect to a receiving standard antenna (coil) which is provided on the insertion part, to detect an inserted condition or state of the insertion part.
Moreover, in a catheter guide device disclosed in Japanese Patent Laid-Open No. HEI 5-177000, an arrangements disclosed in which transmitting means is mounted on the forward end of the catheter or the like, and a signal thereof is received to establish a position of the transmitting means.
Further, an arrangement or the like is disclosed in U.S. Pat. No. 4,176,662 in which burst waves are outputted from a transducer at a forward end of an endoscope, the burst waves are detected by a plurality of surrounding antennas or transducers, and a position of the forward end is plotted onto a CRT.
Moreover, an apparatus is disclosed in U.S. Pat. No. 4,821,731 in which two (2) coils which are arranged outside a body and in the form of a cross are rotatable, and orientation adjacent to a forward end of a catheter is determined or decided on the basis of an output from a loop coil which is provided on the side of a forward end of the catheter which is inserted into the body.
The prior art disclosed in PCT Laid-Open Publication No. GB 91/01431 discloses an arrangement in which a plurality of dipole antennas are arranged in a grating or a lattice manner in X-Y direction around the periphery of a subject into which an endoscope is inserted, and are AC-driven, while a position of the endoscope is led-through or rendered by a signal which is produced by a coil built-in on the side of the endoscope.
However, in the above-described prior art, a method of fixing the coil which is built-in for detecting the position or the form, in the endoscope, or the like has not sufficiently been considered. For this reason, the internal organs or viscera within the endoscope are moved by curvature or bending of an insertion part whenever the endoscope is inserted into a patient. At that tine, a stress is applied to the position detecting coil by friction. Thus, there are situations where the coil is deformed.
If the coil is deformed, the magnetic field which is generated by the coil is changed or varies, or a level of an induced signal is changed. Accordingly, this produces a disadvantage in that it is impossible to perform positional detection or form detection with high accuracy.
Further, the above-described prior art discloses that the coil is arranged within the insertion part which is inserted into an organism, to detect the position of the coil. However, the above-described prior art does not disclose a method of telescopically displaying an image which corresponds to the form of the inserted insertion part, or a means for telescopically displaying the image. Since, generally, the insertion part which is inserted into the organism is curved, it is desirable that the form of the insertion part is displayed so as to be easily visualized.